Skinning method



March 4, 1952 F. J. COAD SKINNING METHOD 5 Sheets-Sheet 1 Original Filed July 18, 1944 INVENTOR D. DECEASED J. coAv ADMINISTRATRIX BY fiy/ TTORNEY FREDERIC J. COA BY MQSFREDEEIC THE SAME PERSON AS GWENDOLYN COAD Ill March 4, 1952 CQAD 2,587,967

SKINNING METHOD Original Filed July 18, 1944 3 Sheets-Sheet 2 I I I I I I I INVENTOR FREDQIC d- COAD DECEASED, BY MRS. FKEDERIC J.CQAD ADMINISTRATRIX THE SAME peesou AS GWENDou/N coAo ATTORNEY March 4, 1952 J, COAD 2,587,967 SKINNING METHOD Qriginal Filed July 18, 1944 3 Sheets-Sheet 3 INVENTOR EEDEEIG J. QUAD, DECEASED ADMINISTEATEIX THE SAME PERSON AS GWENDOLYN cq/w' BY m2 ATTORNEY Patented Mar. 4, 1952 SKINNIN G METHOD Frederic J. Goad, deceased, late of Des Moines, Iowa, by Mrs. Frederic J. Goad, administratrix, Des Moines, Iowa, the same person as Gwendolyn Coad, assignor, by mesne assignments, to Swift & Company, Chicago, 111., a corporation of Illinois Original application July 18, 1944, Serial No. 545,474. Divided and this application August 9, 1948, Serial No. 43,286

6 Claims.

This invention relates toa method for removing skin from meat cuts and more particularly to a method for forcibly pulling skin from a meat shoulder or ham cut.

It is an object of this invention to provide an improved method for pulling skin from a meat out.

It is another object of this invention to provide an improved method for the removal of skin from meat cuts.

Other objects will appear below.

In preparing certain meat items for the consumer trade it is necessary that the skin be removed from the cut, and particularly is this true when ham and shoulder cuts are prepared for the retail trade with the bone removed. Furthermore, skin is a valuable by-product yielding either a high grade gelatin or leather, and therefore, when supplying large volumes of certain cuts to the hotel and restaurant trade Where the skin cannot be utilized, it is removed from these cuts for its value as a by-product.

It has been the practice in the past to remove the skins by a cutting operation, and mechanical cutting means are available to remove the skin from a flat slab of meat. When, however, an irregularly-shaped out, such as a shoulder or ham cut, is to be skinned, it is necessary that a hand-cutting operation be performed to effect a separation of the skin.

In removing the skin from an irregularlyshaped cut by hand, not only is considerable labor involved, but also the labor must be quite skilled. If the skin is to be used in the preparation of leather, it must be removed in an undamaged condition, and yet it is desirable to separate the skin from the out without leaving any meat or fat clinging to the flesh side of the skin. It is seen, therefore, that the most efficient removal of the skin requires the operator to rapidly sever the skin from the meat cut by slicing through the layer beneath the skin. In order then to avoid damaging the skin with the very sharp knives used, it is readily apparent that considerable practice and skill is required before an operator can perform this relatively delicate operation in a rapid manner.

The present invention has been provided to make available an improved skinning method adapted to the removal of skin from an irregularly -shaped cut of meat without necessitating a cuttingoperation such as might injure the skin. It provides a means that may be used, for relatively fixing the meat out while a pulling force is exerted against the skin, and when the pulling 2 force is applied in the right direction, the skin may be peeled off quite effectively without tearing or otherwise damaging the skin.

The present application is a division of my prior application which issued as Patent No. 2,461,466 on February 8, 1949.

The method of this invention may be performed by various mechanical means, and one form of an apparatus adapted to efiectuate the process is shown in the drawings wherein:

Figure 1 represents a side elevation partly broken away of the preferred form of the machine for simultaneously handling a plurality of irregularly-shaped cuts during the skinning operation;

broken away of the preferred form of the machine shown in Figure 1;,

Figure 3 represents a plan view partly broken away of the preferred form of the machine shown in Figure 1;

Figure 4 represents a side elevation of a second form of the machine;

Figure 5 is a plan view of the machine shown in Figure 4;

Figure 6 is a perspective view of a bifurcated hook element shown in Figures 4 and 5 for engaging the meat cut.

In general, the preparation of boned shoulder and ham cuts includes a skinning operation. While the present invention finds particular application to the skinning of such portions of a carcass, it will be apparent as the description proceeds that the invention may find use in the skinning of larger cuts and up to one-half and whole carcasses. These ham and shoulder cuts, however, have a generally irregular shape and thus cannot readily be adapted to a machinecutting operation for removal of the skin from around the entire periphery of the cut. The herein-disclosed invention is, therefore, particularly adapted to the skinning of cuts of this type by a skin-pulling method. When the shoulder and ham cuts are removed from the car cass, the shoulder cut, for example, is severed. so that the humerus bone extends longitudinally through the out. The ham is removed in such a manner that the femur bone extends through the cut. Each of the humerus and femur bones, of course, is formed with an enlarged end where the bones engage the shoulder and elbow joints, or hip and knee joints, respectively.

It has been found that the skin may be rapidly removed from such an irregularly-shaped cut by a pulling action. When the skin is properly Figure 2 represents an end elevation partly 3 prepared and is forcibly drawn from the cut, the fell layer separates and the skin is stripped off without damage to the meat or itself, and it is generally free of all clinging meat and fat particles. This is true with respect to beef and lamb cuts. With pork, however, which has no layer of fell between the skin and the flesh, the skin is similarly peeled off when pulled in this manner, and all fibers normally adhering to the skin are pulled out of the fat and away with the skin as it is pulled from the cut.

To remove skins by pulling, in accordance with this teaching, the cut is fixed in a machine designed for a power-pulling action whereupon the skin is pulled back upon itself so that it is peeled from the meat while being turned at a rather sharp angle as it separates from the cut. The shoulder or ham cut is prepared for skinning by having a tab of skin lifted up on the outside of, the leg cut so that it maybe engaged by suitable clamping means and; in addition, the skin is just cut through along a line generally parallel with the longitudinally-extending bone of the cut on the inside portion of the leg of the animal. The inside out is carefully made so that only the skin is cut. The incision need be no deeper.

When pulling the skin from the cut it has been found that the most satisfactory skin removal results from engaging the skin in a manner such that it is ripped from the cut by reversing the skin upon itself. The fell layer of beef or lamb, for example, is more quickly broken by this procedure because the pulling force is always directly applied to the fell at the fold as the skin folds over upon itself. The fell is comprised of many small fibers interlaced and bonded to the skin and flesh, and this manner of pulling exerts a maximum pull against a fewer number of fell fibers than any other method, so that the fibers are tensioned and broken before the pulling force can be substantially transmitted and distributed through the flesh or other more remote fell fibers. A similar advantage in directing the application of the pulling force substantially to the line of seperation at the fold of the skin is also realized in skinning pork, and the pork skin is easily rolled back upon itself in a manner to be quickly and easily separated from the flesh and fat, together with. all of the little plug-shaped fibrous growths attached to the skin, which heretofore have been left imbedded in the fat layer Whenever the skin was cut free.

A machine adapted to perform this invention is pictured in the drawings, and referring to Figure 1, a ham cut I is shown in position to be engaged by a clamping means to effect a removal of the skin from the cut. The ham out has a femur bone extending therethrough and a skin tab, denoted l2. The femur bone H has an enlarged hip joint end l3 at the butt end of the cut, which may be engaged between one of the pairs of the prongs l4 and I5 forming a holding means for a cut on the skinning machine.

The two pairs of prongs l4 and I5 are fixedly mounted on a suitable movable supporting head I6 slidable in the direction of the arrows shown in Figure 2. The head It may be mounted upon guide tracks I! and I8 for this lateral movement across the machine for a purpose that will appear more fully below, and the two pairs of prongs are supported on the head to hold the meat cut engaged thereby on table l9. Suitable stiffening arms l6 may be fixedly mounted on the side of supporting head l6 which faces the frame of the machine, the arms carrying rollers at their free ends to bear against the frame of the machine in order to brace the hooks against the frame of the machine when the skin-pulling force is applied. It is to be understood, of course, that the skin may be slit on the inside of the leg when the tab is loosened on the outside before the out is placed on the table and between the rongs.

When the ham is so positioned on the table l9 and the end l3 of the bone is firmly engaged between the one pair of prongs I4 and I5, a clamp 20 is fixed to the tab I2 by engagement of jaws 2| and 22, whereupon the clamp 2|] may then be connected to a driven pulling mechanism.

Clamp 20 may take the form of a pincherlike device wherein the jaws 2| and 22 are driven together upon closing of arms 23' and 24. Arms 23 and 24 are normally urged apart by spring 25 and are closed together when links 26 and 21 are pulled outwardly as when chain 28 is connected to the pulling means. This construction provides a clamping device which is normally urged to position for releasing anything engaged between the jaws 2| and 22; yet, when once engaged, and as long as pulling action is exerted, the jaws tend to engage the skin more tightly as the pulling effort increases. As long as the closing tendancy caused by the pullingaction is greater than the contracting force of spring 25, the skin will remain firmly engaged between jaws 2| and 22, and the spring tension is selected to be such that the jaws remain closed until the skin pulling operation is complete.

The flexible link or chain 28 for transmitting the pulling force to the clamp 29 is fixed at. one end to a carriage 30. Carriage 30 is provided with a downwardly-extending hook arm 3| adapted for engagement with the driven pulling means. Carriage 3|) is designed to slide or ride across the top surface of the pulling machine and has suitable bearing members 32 and 33 for supporting the carriage on this surface or slideway. A slot 34, Figure 3, in the surface permits the hook arm 3| to extend downwardly therefrom for engagement with the pulling means.

The .-invention here shown makes use of a pulling means taking the form of a pair of driven chains 40 and 4| carried on suitable sprocket wheels. These two chains are interconnected at spaced points with cross bars 42, and the upper run of the composite chain structure is positioned below slot 34 to cooperate with the hook arm 3| to drive the carriage forwardly in the direction of the arrow as shown in Figures 1 and 3. The chains 4|! and 4| may be driven from any suitable power source to eifect the desired pulling action. 7

The above-described mechanism is operative to engage the skin of any out fixedly held with respect to chains 43 and 4| so that the skin may be pulled therefrom. A cut may be laid on the table l9 and engaged in the machine by forcing the bone between one of the pairs of prongs l4 and I5, as shown in Figure 1. The head It is then adjusted laterally to place the cut generally in front of the slot 34, whereup the jaws 2| and 22 may be closed onto the tab l2 and the chain 28 pulled to clamp the jaws. Then the hook arm 3| is dropped down through slot 34 and between chains 40 and 4| for engagement with one of the cross bars 42 of the driven pulling means. When the hook arm is taken up behind one of the cross bars 42, it is carried forwardly and carriage 3|! rides forwardly on the slideway on the upper surface of the frame of the machine; 1

The forward motion of the carriage 30 through link 28 and clamp 2!] pulls the skin off of the cut progressively from one end to the other by reversing the skin upon itself. The jaws 2| and 22 are, by this action, driven together so that the skin is firmly engaged during the entire pulling operation.

It has been found that when the skin is pulled from a meat cut in this manner, the skin is removed quite satisfactorily without damage to the meat structure itself or to the skin. As soon as theskin is completely removed from the cut, the pulling force against chain 28 is released and the clamp 20 is opened by spring 25 so that the skin may be released. As soon as the skin has been pulled from the out, the carriage 30 reaches approximately the end of the track and the clamp returned to the starting point for attachment to a subsequent cut for skinning.

While one cut is in position and during the skin pulling operation being performed thereon in the machine shown in Figure 1, a second cut may be engaged on the other pair of prongs l 4 and I5. The tab 12 of this second cut may then be raised and engaged onto a clamp 26 so that as soon as the skin-pulling process being performed is completed, the head it may be shifted to move the skinned cut out of position and place the second out before slot 3 3 so that hook arm 3| of the clamping structure fixed to its skin may be dropped into the pulling means. The movable head mounting means l6 for the pairs of prongs I4 and 15 makes it possible for one operator to utilize the machine to the fullest possible extent.

A modified form of the above-described machine is shown in Figure 4, and in this device a bifurcated hook 50, as shown in Figure 6, is provided, having diverging arms for engaging the bone of the meat cut, and a clamp 5| is also provided for fixing to the skin. The jaws 52 and 53 of the clamp are urged together by manipulation of arms 54 and 55 which, in turn, are so connected that when a pulling action is exerted against the clamp, the jaws are driven together. The arms 54 and 55 are interconnected by a link 56 which, at one end, is pivotally connected to the arm 55 and, at the other end, is slidably connected to arm 54 in a suitable slot. The sliding end of link 5% is connected to the chain 51, and any pull exerted on the link 55 by chain 51 causes the lower end of link 56 to slide to the left, as in Figure 4, so that arm 55 is pulled downwardly to drive the jaw 53 against jaw 52.

The clamp is slidably mounted in a movable carriage 66 carried upon the top frame of the machine in suitable slide ways, the clamp being slidable in the carriage on a guide way 61. The carriage i adapted to be driven by a suitable power means such as the air motor 10, and the driven piston of the air motor is connected to the carriage through the connecting rod H, which is fixedly connected to carriage 60.

In the operation of the mechanism shown in Figures 4 and 5, the clamp BI is attached to the skin tab 12, and then the power is supplied to the air motor so that the piston is driven to the left, as shown in Figure 4. When the connecting rod 1| moves to the left, the carriage 60 i carried therewith. The clamp 5| remains stationary until the slack in chain 51 is taken up, whereupon continued movement of the carriage causes the jaws 52 and 53 to be engage-d tightly on the skin flap so that further movement of the carriage causes a drawing action to be applied against the skin so that it is forcibly stripped from the meat cut engaged upon the hook 50.

The motive power to the motor !0 is controlled by a suitable air valve 12 located adjacent the working station of the machine and, by suitable manipulation of the valve, the piston and the air motorcan be driven to the left or right to effect first a pulling off of the skin and thereafter a return of the carriage to its initial starting position whereby the clamp can be engaged on a second cut to effect a removal of the skin.

As above stated, the skin of a shoulder or ham cut is prepared for removal by freeing a tab of skin adjacent the outside of the shoulder or hip joint. The surface on the inside of the animals leg i cut skin deep along a line substantially parallel to the femur or humerus bone disposed in the cut. When the skin is prepared in this manner, the skin may be forcibly pulled off of the out Without damage to the skin or the meat out.

As shown in Figure 1, the out can be laid over on the table with the skin tab on top of the cut so that the clamp may be engaged on the tab and the skin pulled back upon itself as the clamp moves over the top of the cut. In some instances, the out can be more easily placed on the hooks if the cut is handled as shown in Figure 4. In this instance, the cut is merely placed on the hook 5D in such a manner that the skin tab 12 is adjacent the clamp, and when the clamp is fixed to the tab, the cut is allowed to fall over onto the clamp so that the enlarged end of the bone is engaged in the hook as the cut falls onto the clamp. Thereafter, as the clamp is driven out from under the cut, the skin is forcibly drawn off of the meat. The pulling force exerted by the clamp on the tab will aid in turning down the out onto the clamp. It i obvious that the rate at which the cut is turned will depend on how rigidly the cut is placed on the hook and on the amount of the force that is applied to it. In some instances, the cut may be turned more slowly and may not be completely turned down until the skin is partially or substantially wholly removed. The manner of engaging the meat out on the hooks as shown in either Figures 1 and 4 may be used interchangeably with either form of the machine.

The above description of the machine shows its application to cuts of irregular shape. It is obvious that a fiat cut could be fixedly engaged and its skin attached to one of the clamping means so that the skin could be drawn from the cut as described above. The machine is particularly adapted, however, to the removal of skin from irregular cuts such as shoulder and ham cuts where the meat may be separated from the skin by a mere pulling action.

In trimming certain cuts for the retail trade, it is the custom to leave a ring of skin around the hockor shank end of the cut. This may be accomplished in the present machine by cutting through the skin at the hook end before pulling the skin from the meat out. It is likewise apparent that the skin may be stripped from the cut by pulling it from the hook end toward the butt end. The preferred stripping, however, is as above described.

The machine described above is adapted to perform the method of this invention, but it is obvious that other means may be used to turn the skin sharply away from a meat out while simultaneously exerting a pulling force sufficient to strip the skin from the meat. Also, it is to be noted that in some cases where, in skinning pork cuts for example, the skin is more easily pulled free, the skin need not be first severed or cut through to effect its separation. In this instance the skin can be sharply turned and pulled free by main force, it being necessary merely to restrain the out against movement in the direction of pull of the powered pulling means. The cut is, of course, set up with respect to the driven pulling means so that the skin breaks free from the cut at a relatively sharp angle.

Many modifications of the invention disclosed herein may occur to those skilled the art. While the invention has been described and illustrated with means for holding the cut stationary while pulling the skin, it is readily apparent that the skin could be fixed and the cut moved. A single or plural grouping of pulling means may be associated with clamping means to hold the cuts, but as shown in the preferred form of the machine as shown in Figures 1 and 2, a single pulling means is adapted to cooperate with a plurality of holding means. All such modifications are considered to be within the scope of the following claims.

What is claimed is:

1. A method of skinning meat pieces comprising loosening the skin at one edge of the piece with the piece disposed so that saidedge is in rearward position, holding the loosened skin against forward movement, and moving said piece forwardly while permitting the piece to turn as the skin is removed therefrom.

2. A method of skinning a meat piece containing a butt and a shank portion comprising securing against forward movement an edge of skin on said butt portion with the shank portion disposed forwardly, and moving said piece forwardly while permitting the same to turn as the skin is removed to thereby cause the skin to turn inside out as it is removed from said shank portion.

3. A method of skinning a piece of meat comprising'grasping and holding against forward movement an edge of skin at one end of said piece, grasping the meat piece at said end, and separating the skin and meat so grasped while turning said end of the meat piece away from said skin edge, to thereby separate the skin from the meat piece.

4. A method as in claim 3 wherein said meat piece is grasped about a bone structure thereof.

5. A method of skinning a piece of meat comprising grasping and holding against forward movement an edge of skin at one end of said piece, grasping the meat piece at said end and. holding the meat piece against rearward movement, and separating the skin and meat so grasped by a forward movement of the meat piece while turning said end of the meat piece away from said skin edge, to thereby separate the skin from the meat piece.

6. A method of skinning a piece of meat comprising grasping and holding against forward movement an edge of skin at one end of said piece, grasping the meat piece at said end and holding the meat piece against rearward movement, and separating the skin and meat so grasped by a rearward movement of said edge of skin while turning said end of the meat piece away from said skin edge, to thereby separate the skin from the meat piece.

Mas. FBEDERIC J. CQADL Administratrz'aq, same person as Gwendolyn Goad, of the Estate of Frederic J. Goad, deceased.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,878,457 Berry Sept. 20, 1932 1,960,643 Lorenzen May 29, 1934 

